Mixing and separating apparatus



Feb- 8 1949- E. R. KANHOFER MIXING AND SEPARATING APPARATUS 'Filed Feb. 25, 1945 lllll `an alkylation process.

Patented Feb. 8, 1949 MIXING AND SEPARATING APPARATUS Elmer R. Kanhofer, Riverside, Ill., assignor to Universal Oil Products Company, Chicago, Ill., a corporation of Delaware Application February 23, 1945, Serial No. 579,441

(Cl. 23-285l 6 Claims.

This invention relates to a mixing and separating apparatus wherein fluids are mixed and contacted in one zone and then centrifuged in a second separating zone to eiect a relatively complete separation of the uids into light and heavy phases. The apparatus is especially useful in the contacting of substantially immiscible liquids and in maintaining the liquid of highest specific gravity within the apparatus. The operation of the apparatus is such that the liquids being handled may pass continuously through the contacting and separating zones of the apparatus.

One object of the invention isrto prov-ide an ap paratus combining the mechanical* mixing and separating operations within a single chamber. Another object is to provide an apparatus in which the mixing rotor and the centrifuge paddles are driven by a single drive shaft.

Still another object is to provide an apparatus which may be substituted for the usual mixing and separating chambers and the accompanying pipe lines, pumps, etc.,- these being necessary when the separating chamber is remote from the mixing zone.

Still another objectV is to provide an apparatus which can return the heavy centrifuged liquid phase from the separating zone directly to the mixing zone', so that it can again be used as a .contactingliquid lin the mixingV zone- This improved apparatusV is of particular value in: connection with chemical processes ern-pioying-liquid catalysts or treating agents. For exalkylated hydrocarbons can be withdrawn` from the upper part oi the chamber substantially freeY There are many types of mixers using rotating plates, or propellers, or rotors' and straightening vanes, also there are various types of centriiuging apparatus, making use of rotating disksrotating` bowls `or revolving plates. However, the mixing and separating operations are not ordinarily carried out within the same housing or chamber and in the usual centrifuging operation the light and heavy components are separatedl from one another and separately discharged from the device. In this invention,l baiiles and spiral varies areprovided to flow the heavier centrifuged liquid phase along the inside of the chamber wall and return it directly to the lower part of the mixing section, so that it may again be used as a contacting material.

ample, in the alkylation of hydrocarbons, isopar- The reactants actions, into a reaction zonet where good contact is obtained and wherefrom the products are passed to` suitable separating and recovery apparatus.

The. use of mixing blades or rotors generally provide. the greatest eiiiciency for agitating and contacting liquid materials Aand for obtaining an emulsion-like mixture which isv very desirable in Also. use of mechanical oentrifuging is more rapid and eiiicient thanv is gravity separation, so that in connection with; the alkylation. of hydrocarbons, the emulsion of hydrocarbons and acid from the mixing zone may adi vantageously pass Vto an adjacent centriiuging zone.` In the centrifuging zone of the apparatus of this invention, the heavier acid is thrown to the outer wal-l of the chamber and returned to the mixingor contacting zone. ior reuse, While; ,the

In the preferred embodiment of this combined contacting and separating apparatusfthe mixing `and centrifuging sections are housed within a single cylindrical and vertical positioned cham.- ber. The mixing section is in the lower part oi the chamber and is separated from the upper centrifuging section by a horizontal baiiley plate which has a central opening for upward iiow of liquid therethrough and for a drive shaft. A single axial positioned drive shaft' extends through the adjacent mixer and separating zones. Ari eiectrical motor or any other desired type of'prin e mover may be used to turn the shaft and revolve a turbine-type rotor mounted thereon in the mixing zone and paddle type blades mounted thereon in the centrifuging zone. A .plurality of straightening vanes are placed just clear of the outer pee riphery of the turbine type of rotor in the mixing zone. An inner shell or baille circumscribes the mixing zone and connects to the horizontal baffie plate which separates the upper and lower sections and is spaced a short distance from the outer chamber wall in order to provide an annular space for flow of the heavy centrifuged liquid from. the upper separating zone to the lower part of the mixing tone..l Inlet-means are provided to .irr-

troduce liquids into the mixing zone at the lower end of the chamber and outlet means to discharge the lighter centrifuged liquid of the reaction product from the upper section of the chamber.

Various modifications may be made to the apparatus of this invention, spiral vanes may be placed on the inside of the chamber Wall in the upper zone to direct flow of the heavy centrifuged liquid along the outer wall to the annular passage space provided and to the lower part of the vessel in the mixing zone. Also these straightening vanes may be made hollow to have a cooling or heating medium ow therethrough and act as a cooling or heating coil in the reac-f tion zone. perature is very critical, such that the additional temperature control thus provided by the vanes may be very important. The dual use of the straightening vanes also eliminates need of additional cooling pipes or coils in the chamber.

The accompanying diagrammatic, drawings illustrate one form of a combined mixing and separating apparatus embodying the principal fea- `tures of the invention.

Figure l is a sectional elevation View of the improved apparatus.

Figure 2 is a sectional plan of the lower portion of the apparatus as indicated by the line 2 2 shown on Figure 1.

Referring to Figure l, the numeral I refers to the outer cylindrical housing or shell ofthe apparatus, the lower'head 2, in the case illustrated, is integral with the shell, while the upper head 3 is in the form of a cover plateY detachably secured to the upper iiange 4 of the shell l by bolts 5.

An inner cylindrical shell or baiile 6 and the horizontal disc-like baffle 6' serve to separate the lower mixing zone 'l from the upper separating zone 8. The horizontal baille 6 should be detachably fastened to the inner shell 6 as indicated for assembly and construction purposes. A rotatable shaft 9 extends through the apparatus and the packing glands lll and II on the respective uppe r and lower heads of the housing. The lower end of the shaft 9 is shown terminating in an outboard Vthrust bearing I2, while the upper end of the shaft may be connected by a flexible coupling or gearing, or any other desired means (not shown), to any desired type of motivating means, such as an electric motor.

A turbine type of rotor I3 is attached to the shaft S in the lower part of the mixing zone l, the blades to this rotor may be curved as shown, or ,they may be substantially straight. The function of this lower rotor I3 is to give the entering liquid a swirling, turbulent motion and obtain intimate mixing and contact between all the liquids. Stationary curved vanes i4 are placed around the interior of the mixing zone, to act as straightening vanes for fluid ilow in the mixing operation. These straightening vanos I4 are shown to be of hollow construction, such that they may also serve as cooling ns'. A cooling fluid inlet connection l5 and a distributing header i5 are shown below the varies I4 while an outlet header il and an outlet conduit connection if: are shown at the top of the plurality of vanes l This cooling modification is optional, since it may be unnecessary in some processes, but ofV value in others.

Paddle type blades I9 are attached to the shaft in the separating section 8 to provide a centriinging swirl to the liquids entering this zone. The

-uids enter this zone through the enlarged open- In someprocesses the reaction tem- Vzo ing around the shaft in the horizontal baule 6'. The inlet nozzles 2i! and 2i, in the lower head 2, are used to admit the reactants and treating materials into the mixing zone l', while the outlet 22 in the upper part of the separating zone 8 is used to withdraw the reaction product, or products, after contact with the heavier catalyst or treating agent. Spiral-type vanos 23 vare provided around the inside of the outer shell I in this upper zone as an aid in directing the flow of the heavier centrifuged liquid into the annular space between shells I and li, which leads to the mixing zone 'i'. A small continuous baule 24 is shown in the lower portion o the mixing zone, to prevent the effect of the rotor I3 from disturbing the downward cw of the heavy liquid from above. This bafe 2li. as well as the baiile 6 and the set of straightening vanes I4, may be supported from the housing by suitable uns or struts, which are not illustrated.

The nozzle 2E on the side of the outer shell I may be used to withdraw a portion of Vthe heavy liquid phase from the annular space between shells I' and f.

In the Figure 2, a sectional plan view of the apparatus is shown as indicated by the section line 2 2. The various parts shown in plan are numbered to correspond to the numbers attached in Figure l. l Y Y It will be noted that in the specic form of the apparatus illustrated that by the removal ofthe bolts 5, that the cover and the shaft assembly including the rotors can be removed from the chamber or housing I. rThe bailie plate E can be detached from above and removed with the shaft and rotors. The rotor I3 and the blades I9 are preferably joined to the shaft c by keys, set screws or other means, not illustrated, Awhich permit their easy removal from the shaft. All

it portions oi the apparatus are thus made readily accessible for inspection, replacement and repair. To illustrate the operation of the apparatus of this invention, it will be assumed that it is to be used in connection with the alkylation of hydrocarbons, using hydrogen fluoride as a catalytic contact agent.

A mixture of isoparafns and olens, principally isobutane and butylene, are charged ycontinuously to the apparatus through inlet 20, while the hydrogen fluoride catalyst is introduced through inlet 2 I. The products are well mixed and emulsied in the lower zone' l, aided by the revolving turbine-like rotor I3 and the vanes I. Thereaction, which produces almost entirely parain hydrocarbons with isooctanes predominating, takes place at ordinary cooling water temperature. Thus, when using hydrogen fluoride, cooling water can be circulated through rthe vanes I4, entering through inlet I5 and exiting through outlet I8. However, for other processes, such as the alkylation process using sulfuric acid ,as a .catalyst a lower reaction temperature is desirable and a refrigerant may be circulated through the vanes I4 in order that they act as cooling fins in the reaction zone. l

The emulsion or mixture of hydrocarbons and catalyst passes to the upper zone through the central opening in the baille 6'. The large revolving paddles I 9 serve tc centrifuge the iiuids and throw the heavier hydrogen iluoride to the out- Vside wall I and then direct it by vanes 23 down into the annular space between shells I and 6. rThe hydrogen fluoride has a much higher specific gravity than the hydrocarbon product, it is also relatively irniniscible with the reactants or rea catalyst in contacting the incoming hydrocarbon reactants entering the chamberthrough inlet 2D. After initial start up and the estab'-l lishment of proper hydrocarbon to catalyst ratio, then the hydrogen fluoride acid feed introduced through inlet 2l need only be enough to make up for the relatively small amount of catalyst which may be dissolved or entrained in the product stream being withdrawn, and which may be withdrawn through nozzle j for regeneration.

bottom of the lower section, a rotatable drive shaft extending vertically through the chamber and through the central opening of said baille, f the drive'shaft being of smaller cross-sectional areathan said opening, a mixing rctor secured to the shaft in said lower section, a plurality of vanes disposed vertically within the lower section be- It is advisable in the alkylation process to have some provision for regenerating the acid catalyst which tends to accumulate hydrocarbon tars and water. A constant withdrawal of a portion of the acid may be made through the nozzle 25 `and then be ysent on to proper regenerating equipment.

It is not intended to limit the use of this combined mixing and separating apparatus to the;

alkylation of hydrocarbons, since there are undoubtedly many other chemical or treating processes which may well make use of this-invention. Y

It is also not intendedtolimit the construction to the particular details shown or mentioned iny the abovel'description. For instance, a propeller type of blade may be preferable in some mixing operations to the lower lrotor and straightening vanes which are indicated in the mixing section. In the upper centrifuging zone, a diierent type of rotating blade or device maybe used in place of the paddle type of blades I9 which are illus-` trated. Thus, it can be noted that variousrmodfV ications of mechanical and structural details may be made and still come within the scope of this invention.

I claim as my invention:

l. A mixing and centrifuging apparatus comprising a cylindrical chamber, a circular baille disposed horizontally within said chamber and dividing the chamber into a lower section and an upper section, said baflle terminating short of the inner wall of the chamber and having a central opening, a cylindrical shell ldepending from said baille adjacent the outer periphery ofthe latter into said'lower section and terminating above the bottom of the lower section, a rotatable drive shaft extending vertically through the chamber and through the central opening of said baille, the drive shaft being of smaller crosss-ectional area than said opening, a mixing rotor secured to the shaft in said lower section, and a centrifuging blade secured to the shaft in said upper section. e. l

2. A mixing and centrifuging apparatus comprising a cylindrical chamber, a circular baille disposed horizontally "within said chamber and baille adjacent the outer periphery of'thelatter;

into said lower section and terminatingabove the tween said rotor and said shell, and a centrifuging blade secured tothe shaft infsaid upper section.

3. AY mixing and centrifuging apparatus comprising a cylindrical chamber, a circular baille disposed horizontally Within said chamber and dividing thechamber into a lower section and an upper section, said baille terminating short of the inner wall of thechamber andhaving a central opening, a cylindrical shell depending from said baille adjacent the outer periphery of the lattery into said lower section andrterminating above the Vbottom of the lower section, a rotatable drive shaft extending vertically through the chamber and through the central opening of said baille, the l drive shaft being of smaller cross-sectionalarea than said opening, a mixing rotor secured `to the shaft in said lower section, a centrifuging blade. -secured to the shaft in saidy upper section, and

baffling means constructed and arrangedwithin said upper section to direct liquid from the upper and the chamber wall.

4, The apparatus as deflned in claim 3 further characterized in that said baffling means corn-A prises spirally arranged vanes secured to the chamber wall within said upper section.

5. A mixing and centrifuging apparatus comprising a cylindrical chamber,.a circular baille disposed horizontally within said Ychamber and dividing the chamber into a lower sectionand section `into the annular space betweensaid shell an upper section,V said baille 'terminatingYY short of the inner wall Aof the chamber and havingra central opening, a'cylindrical shell depending, from saidbafileadjacent the fouterperiphery of the latter into `said lower section and terminatingV above the bottom ofthe lower section, a rotatable drive shaft extending vertically through the;

chamber and through the central opening of'said baille, the' drive shaft being of smaller crosssectional area than said opening, a plurality of curved blades secured to the shaft in said lower section, a centrifuging paddle secured to the shaft in said upper section, a plurality of vanes disposed vertically within the lower section'between Y said blades and saidshell,` and directing vanesarranged spirally along theV chamber wallin the vupper section,

6. The apparatus as defined in claim Zfurther characterized in that vsaid vanes are of hollow construction and are provided withv conduitsV for circulating a heat exchange fluid therethrough. Y

iuirnmiiyCEsv CITED- 'Ihe following references are of record in the le of this patent:

UNITEDl STATES PATENTs,

l Hadden j -10ct. 9, 1945 

